1. Field of the Invention
The invention relates to a composite light guiding film module, and in particular relates to a light guiding film module having a plurality of optical elements guiding light into a light guiding film and propagating therein.
2. Description of the Related Art
Mobile devices, such as mobile phones, PDAs, or digital cameras, have a side backlight module. Meanwhile, as smaller sizes are preferred, an extra-thin light guiding film is desired. When the light guiding film has a thickness less than 300 μm, it is difficult to direct light into the film from edges thereof. When the light source is a light emitting device (LED), light beams from the LED converge, and, therefore, can be directed into a thinner film than a cold cathode fluorescent lamp (CCFL) can. When the film is too thin, even light beams from LEDs cannot be directed into the film from edges thereof. A complicated method and system must be employed to couple light beams to the film. An application (application Ser. No. 11/950,344) of the applicant of the invention discloses a light guiding film having light diffusion structures which guides light into the light guiding film. There is light loss caused by partial penetration of the light guiding film.